Uniform tension winding mechanism



Sept. 16, 1958 J. H. WALLACE 2,852,130

UNIFORM TENSION WINDING MECHANISM Filed Oct. 26. 1953 3 {kl- N E WZLLACE,

INVENTOR.

T'TORA IEY.

Sept. 16, 1958 J. H. WALLACE 2,852,130

- UNIFORM TENSION WINDING MECHANISM Filed Oct. 26. 1953 .s Sheets-Sheet 2 ATTOQNEY.

j INVENTOR. 5Z3 @7 54 6) IE/ 1v E MLLACE,

Sept. 16, 1958 .1. H. WALLACE 2,852,130

UNIFORM TENSION WINDING MECHANISM Filed Oct. 26. 1953 3 Sheets-Sheet 3 M II (IO/10V I]. MLLACE,

INVENTOR.

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ALTOA/EK United States Patent UNIFORM TENSION WINDING MECHANISM John H. Wallace, Milford, Conn., assignor to U. S.- Electrical Motors, Inc., Los Angeles, Calif., a corporation of California Application October 26, 1953, Serial No. 388,380

Claims. (Cl. 198-208) This invention relates to a transmission mechanism, controls therefor, and particularly to a transmission mechanism and its controls for maintaining certain conditions of operation constant.

In order to ensure quality and to meet the. sometimes exacting requirements of users of wound material, such as fabric or paper, it is highly desirable that the material be wound at a constant tension, with appropriate tolerances. Since the radius of material upon a winding or take-up roll increases in proportion. to the amount of material already wound, a substantial variation intension of the. material may result therefrom. In order that the-material be wound at a constant tension, some form of correction must be made. If the linear rate at which the material. is to be wound is constant, then it is apparent that the. speed of the winding roll must decrease to compensate for. the increased radius.

A decrease in angular speed of the winding roll in proportion to the increase in radius is the ideal relation that. would maintain constant tension in the material wound. Solutions have been proposed, such as slipping clutches of various kinds, or more complicated control mechanisms. Slipping clutches, though simple, are subject to, the disadvantage that they require extensive maintenance, and their operation is not sufficiently reliable to achieve constant tension within small tolerances.

It is an object of the present invention to make. it possible to achieve a substantially constant tension in material wound upon a roller, all by the aid of simple apparatus. The advantages and desirable results of constant tension, such as avoiding slippage and damage between successive layers of material, is then obtained.

To accomplish this purpose, a variable ratio transmission mechanism is utilized in which the transmission is adjusted through a continuous range to maintain the input shaft torque to the transmission constant. Adjustment is made by a control system responsive to movement of a ring gear, the ring gear being movable in accordance with the torque. The input shaft torque is. made to be proportional only to the tension of the ma? terial being wound, specifically by feeding the materialat a linear rate proportional only to the angular speedof the. input shaft.

It is another object of this invention to provide a transmission system that maintains tension in a web or conveyor belt constant.

It is another object of this invention to provide a drivefor a pump that maintains the output pressure of the pump constant independent of flow conditions from the pump. For this purpose, a variable ratio transmission mechanism operates the pump, and a control systemre-' sponsive to the torque requirements of the pump varies the setting of the variable ratio transmission mechanism to maintain the torque constant. Accordingly, the output.

pressure of the pump is maintained constant independent ofthe. flow requirements placed upon the pump by variation in the operation of hydraulic mechanisms supplie by the" pump.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent. from. a consideration of several embodiments of theinvention. For this purpose, there are shown a few forms. in. the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description. isnot' to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure lis a diagrammatic view of a winding apparatus: embodying the present invention;

Fig.2; isa longitudinal sectional view of a transmission apparatus, forming a part of the present invention;

Fig. 3- is a sectional view, taken along the plane indicatedi by line 3-3 of Fig. 2;

Figs. 4, 6 and 7 are diagrammatic views of a transmission apparatus, each forming other embodiments of the present invention;

Fig. 5 is a view taken in the direction indicated by;

linesS-Sof Fig. 4; and

Fig. 8 is a. diagrammatic view illustrating a typical structure for varying'the ratio of transmission.

In the form shownin Figs. 1 to 3, a continuous length of material 10 is intended to be Wound upon a roller or take-upspool 11'. The roller 11 may be of any suitable form; In the present instance, it is provided with guiding flanges 12 at its opposite ends. An output shaft 13 of a variable ratio transmission mechanism 14, to be described more fully hereinafter, drives the roller 11 at a speed ratio dependent upon the setting of its operating mechanism' 9 The variable ratio transmission 14 is adjustable continuously. Any one of an infinite number of settings, within limits, may be achieved. An input shaft 15 for the mechanism 14 is driven through a differential trans mission 16, in turn operated by a shaft 17. A pulley structure, comprising pulleys 18 and 19 and a flexible V-helt' 20, connects an input shaft 21 of the differential transmission 16 with the shaft 17. An appropriate source of rotary motion operates the shaft 17.

The shaft 17 carries a process roller 22 around which the material 10 is looped. A slack feed may precede the roller 22'. The roller 22 is appropriately aligned with the winding roller 11 and serves to feed the material 10. to the winding roller 11 at a rate directly'proportional to the speedof the shaftl'i The power requirement at the roller 11 is proportional to two'quantities, namely, the tension in the material 10 multipliedby the linear rate at which the material" 10 is supplied. The linear rate at'whichthe material 10is supplied ig'governed by and directly proportional only to the *angular'speed of'thesliaf't 17, since the etfectiveradius of tlie'process roller 22 remains invariant; However, since the shafts*15- and 21 are directly coupled to the shaft 17;

the p'ower requirement to the roller 11 can be considered fore; if then the ratio of the power required at the roller 11 to the speed of the shaft 15 is maintained constant;

the tensionin thematerial lfimust remain constant by,

virtueof-these considerations.

'Fhe: ratio of power at the' roller 11 to the angular velocity of the shaft 15 corresponds to the torque of' the shaft 15,.sincesthe. power atthe: shaft 15 is proportional to the power at the roller 11. Accordingly, if the torque delivered by the shaft 15 remains constant, the tension in the material must remain constant.

By providing a mechanism responsive to a change in the torque at the shaft for producing a correcting effect so that the torque is maintained within critical limits, the tension in the material 10 may similarly remain constant. The differential transmission mechanism 16 is intended to incorporate a member movable in accordance with a change in the torque.

The differential transmission 16 incorporates a planetary gear structure that is housed in a two-part casing 25. The input shaft 21 to the mechanism 16 carries a driving sun gear 27. The shaft 15, forming the output from the mechanism 16, carries a plurality of driven planetary gears 28 that are in engagement with the sun gear 27. For this purpose, the shaft 15 carries a mounting or spider 29 for rotation therewith. The planetary gears each have shaft extensions 30 that are journalled in appropriate recesses 31 of the mounting 29. The end of the shaft 21 is piloted in an axial recess 26 of the planetary gear mounting 29.

A ring gear 32 having internal teeth engages the outermost portions of the planetary gears 28. The ring gear is secured to the housing 25. Appropriate fastening means 33 are provided for this purpose.

The entire casing 25 is rotatably supported about the axes of the shafts 21 and 15 by the aid of suitable bearing structures 35.

If the housing 25 and ring gear 32 are held stationary, rotation of the sun gear 27 in the direction of the arrow 34 causes the gears 28 to rotate in a planetary fashion in the same direction. The planetary movement of the,

gears 28 causes corresponding rotation of the shaft 15.

The manner in which the ring gear 32 and housing 25 are held substantially stationary will be described more fully hereinafter.

The ring gear 32 absorbs an invariant proportion of the reaction torque of the shaft 15, which torque tends to move the ring gear 32 and the casing 25 in the direction of the arrow 37. This torque is counterbalanced, however, and opposed by the aid of a spring 38. For this purpose, the spring 38 is attached at opposite ends to a stationary support 39 and a radially extending arm 40 carried by the casing 25.

Assuming that the position of Fig. 3 corresponds to a definite torque reaction upon the ring gear 32 and casing 25, balanced by the spring 38, it is apparent that an increment in torque reaction will serve to move the casing 25 angularly in the direction of the arrow 37. The amount of such angular movement is dependent upon the constant of the spring 38.

Since the shaft torque at shaft 15 is directly proportional to the tension in the material 10, the arm 40 is angularly positioned not only in an amount dependent upon the torque, but actually in an amount proportional to the tension in the material 10.

Let it be assumed that the mechanism 9 is at a particular setting. Then the ratio of the angular velocity of the winding roller shaft 13 as compared with the angular velocity of the process roller shaft 17 is constant. This is true despite the fact that the shaft 17 may be driven at diiferent angular velocities throughout the period now under consideration. However, due to the fact that the material 10 is being continuously wound upon the roller 11, the increase in radius of the winding roller would be accompanied by a corresponding proportionate increase in tension in the material 10. This follows in that, for a given setting of the mechanism 9, the linear rate at which the roller 11 takes up the material 10 is increasing as compared with the rate at .which the roller 22 is supplying material. The actual speed of operation of the shaft 17, be it large or small, does not prevent such increase in tension. The speed of the shaft 17 only determines how fast this tension will increase.

The increased tension of the material10, combined with an increased radius, results in an increasing torque requirement to the system. This increased torque (tension of material 10) causes movement of the arm 40 in the direction of the arrow 37. The tension in the material 10 can be reduced only by decreasing the ratio of the angular velocity of the winding roller shaft 13 as compared with the angular velocity of the process roller shaft 17. This ratio is, of course, independent of the actual speed of the shaft 17 A control system 41, responsive to an increase in torque (tension of material 10), through the angular movement of the arm 40, is adapted to reduce the ratio of the speed of the winding roller shaft 13 as compared with the process roller shaft 17. Such reduction in the speed ratio thus corrects the condition to which it is responsive. This is made possible by a circuit controller operated by movement of the arm 40. For this purpose, a spring contact arm 42 carrying a contact 43 is insulatingly mounted upon an arm 44 of the stationary support 39. The arm 40 of the casing part 25 likewise insulatingly mounts a contact 45 that is engageable with the contact 43 upon movement of the arm 40 angularly in the direction of the arrow 37. An appropriate circuit to the control system 41 is then effected through the a lead 46 connected to the contact 43, engagement of contacts 43 and 45, and a lead 60 connected to the contact 45. This is diagrammatically illustrated in Fig. 1.

The control system 41 then operates the variable ratio transmission mechanism 14 to reduce the ratio of the speed of the winding roller shaft 13 as compared with the process roller shaft 17.

Such decrease in speed ratio may be accomplished by the aid of relatively axially adjustable cone pulley elements 47 cooperating with a flexible belt 48. The flexible belt 48 cooperates'with a second set of relatively axially adjustable cone pulley elements 61 supported on the shaft 13. The belt 48 engages the pulley sets 47 and 61 at radii depending upon the spacing between the elements of each set. Upon movement of the elements 47 closer together, with a corresponding movement of the elements 61 farther apart, the belt 48 will be moved faster to increase the speed of the shaft 13. Conversely, as the elements 47 are moved apart, with a corresponding movement of the elements 61 closer together, the belt 48 moves more slowly to slow down the shaft 13. Corresponding opposite relative movement of the elements of each set is necessary to maintain constant tension in the belt 48. The control system 41 operates the mechanism 9 that adjusts the spacing of the elements 47 and 61.

In Fig. 8, the pulley sections 47 are illustrated in more detail. The upper pulley section is carried on the shaft 15; and the lower pulley section 47 has a central hub 103 mounted upon a sleeve 101 rotatably coupled or splined to, but axially slidable with respect to, the shaft 15. The inner race of a roller bearing structure 102 is held by a nut 104 against the end of the hub 103.

The outer race of the bearing structure 102 mounts a ring 105. By virtue of the bearing structure 102, the ring 105 may be non-rotary. A lever 106, pin-connected at one end to the ring 105 as at 107, shifts the ring 105 in a direction axially of the shaft 15. The other end of link 106 is connected as at to a shifting nut 109. The nut 109 is shifted by a lead screw 108. As the lead screw 108 is rotated in one direction, the nut 109 moves to the left and causes the link 106 to assume a more perpendicular relationship with respect to the lead screw 108. Accordingly, the pin connection, as at 107, is shifted upwardlypand the ring 105, bearing structure 102 and the lower pulley section 47 are correspondingly shifted. Opposite movement of the lead screw 108 retracts the link 106 and the ring 105.

For rotating the lead screw 108, a reversible motor 11 is provided. The motor, through reduction gears 112 and 113, causes rotation of the lead screw 108. The

reversible motor 111 is controlled by the control system 41 (Fig. 1.).

Mechanisms of this sort are shown, for example, in Patent No. 2,257,744, in the name of Don Heyer, issued October 7, 1941, and Patent No. 2,398,235, in the name of Frederick O. Luenberger, issued April 9, 1946.

A reduction in the speed ratio of the shaft 13, such as is brought about by the control 41 conditioned or energized by the lead 46, brings about a proportionate reduction in the tension in the material 10. The reduced tension then permits the arm 40 to move from contacting position.

Over-compensation for speed ratio may be corrected by the control 41 operating the variable ratio transmission mechanism 14 to increase the ratio of the speed of the shaft 13 as compared with the shaft 17. This may be effected by a circuit controller operated by the arm 40. For this purpose, a spring arm 49 that insulatingly mounts a contact 50 is mounted on another arm 51 carried by the stationary support 39. The arm 51 and contact 50 are on that side of the movablearm 40 remote from the first arm 44- and its contact 43. Thecontact 50 is engaged by a corresponding contact 52 insulatingly mounted on the arm 4%). Engagement of the contacts 50 and 52, corresponding to a reduction in power, energizes or conditions the control 41 through a lead 53 connected to the contact 50, engagement of contacts 50 and 52, and the lead 60 also connected to contact 52. Such energization or conditioning of the control system 41 operates to move the cone elements 47 together and theelements 61 apart.

The spacing between the contacts 43 and50, efiecting alternate operation of the control 41 and variable. ratio transmission mechanism 14, together. with the geometry of the system including the constant of the spring 38, determines the tolerable variation of the tension in the material 10. Adaptations of the system can easily be made to adjust the range or tolerance of the tension in the material 10. Thus, for instance, adjustable mount-- ings could be provided for the contacts 43 and 50 upon the support 39. Optionally, a spring of different spring constant could be substituted.

The actual desired tension of the material 10 could be adjusted by providing an adjustable attachment for. one end of the spring 38 so that the tension exerted thereby for the intermediate position of the arm 40 is determined.

The system is entirely symmetrical so that it can be utilized to control the tension of the material should it be unwound.

By the arrangement of the elements in the system, a constant tension for the material 10 is achieved, despite the fact that the radius of the winding roller increases and despite even extreme variations in the speed of .operation of the driving shaft 17.

In the form shown in Figs. 4 and 5, a web 70, or the like, is intended to pass between spaced pairsof process rollers 71, 72 and 73, 74; The left-hand pair of process rollers 71, 72 operates to move the web 70; the right-hand pair of process rollers'73, 7'4 guides the web 70 and serves to feed the web 70 toward the driving rollers 71, 72.

An appropriate source of rotary motion operates the feed rollers 73, 74. The driving rollers 71, 72 are. driven through the variable ratio transmission mechanism 14 connected to the differential transmission mechanism 16. The differential transmission mechanism 16 is operated from the shaft 76 of one of the pair of feed rollers'73, 74 by the aid of pulley structures 18, 19. The general organization of structure is substantially the same as in the previous form.

The tension in the web 7 is proportional to theto'rque reaction in the shaft 77 between the variable ratiotransmission 14 and the planetary transmission 16 for" the reasons discussed in the previous form.

The present system operates to maintain the tension in theweb 70 constant through the governing action of the feed rollers. 73, 74 and the operation of the drive rollers 71, 72 by the variable transmission mechanism 14 and the torque responsive ditferential transmission mechanism 16..

The-effective radii of the driving rollers 71, 72 remain constant; but this fact simply removes. a variable factor as compared with the form shown in Fig. 1. Accordingly, the ratio of transmission 14, instead of beingcontinuo-usly reduced to compensate for an increased radius as in the previous form, stays within narrow pre-set limits.

In the form shown in Fig. 6, the. transmission system is utilized to drive a conveyor beltw80. The variable ratio transmission mechanism 14 operates sprocket wheels; 81 and 82 in engagement with chains 83 and 84 at the sides of the conveyor 80. The conveyor is fed to the driving sprockets 81 and 82-at'agoverned rate by sprocket wheels 85 and 86 connected to a shaft 87.

The shaft'87, by the aid of pulleys 18' and 19, operates the planetary transmission 16. The co-ntrol system 41, operated by a change in torque from. a pre-set valve at the planetary transmission 16, adjusts the variable ratio. transmission mechanism 14 to maintain tension in the conveyor 80 constant, as in the previous forms.

In the. form shown in Fig- 7, a hydraulic system is shown. A rotary pump 90 supplies fluid to a main conduit 91. Branch conduits 92, 93, 94 and 95 may supply hydraulic motors or other hydraulic mechanisms.- Flow of material in each of the branch conduits. 92, 93, 94'- and 95 is individually controlled by valves 96, 97, 98 and 99.

In order that the fluid mechanisms supplied'bythe:

branch conduits 92, 93, 94 and 95 operate properly, it

is important that the pressure supplied thereto be con-- stant.

and thus perhaps improper operation of the hydraulic.

mechanism operated through the branch conduits 92, 93,.

94 and 95.

'In order to maintain constant pressure in the main. conduit 91 supplied by the output of the pump 90 inde pendent of the setting of the valves 96, 97, 98 and 99, the rate of operation of the pump may be adjusted in accordance with the demands of the entire system.

The torque reaction on the pump rotor is directly dependent upon the output pressure. Thus, if the torque reaction on the rotor of the pump 90 is maintained to a pre-set limit independent of flow conditions in the conduit 91, the pressure in. the conduit 91 will likewise be constant.

The variable transmission mechanism 14, driven by a motor 100, operates the pump 90 through the planetary transmission mechanism 16. The variable ratio trans mission 14 is such that the ratio of transmission can increase sufiiciently to operate the pump 90 at an enhanced rate which will be sufficient. to provide the high. pressure required should all of the valves 96, 97, 98 and.

1. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft con-- nected to said first rotary member; a second rotary member for moving the belt and spaced from said first rotary member; a variable ratio transmission mechanism for operating said second rotary member, and having an input shaft operated by said driving shaft; and means responsive to the torque load on said input shaft for varying the ratio of transmission to maintain said torque load within predetermined limits.

2. In a control system of the class wherein a load is operated by a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, the combination therewith of: a differential transmission including a driving member, a driven member, and a reaction member; means supporting the reaction member for limited angular movement; resilient means restraining movement of said reaction member; and a circuit controller operated upon movement of said reaction member for controlling said electrically operable means.

3. In a control system of the class wherein a load is operated by a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, the combination therewith of: a planetary gear structure including a planetary gear element, a sun gear element, and a ring gear element; one of said elements being a driving element, another of said elements being a driven element, and the other of said elements being a reaction element; means supporting the reaction member for limited angular movement; means resiliently restraining movement of said reaction element from one position; and a circuit controller operated upon movement of said reaction element from said one position for controlling said electrically operable means.

4. In a control system of the class wherein a load is operated by a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, the combination therewith of: a differential transmission including a driven member, a driving member, and a reaction member; means resiliently restraining movement of said reaction member in'either direction from one position; a first circuit controller operated in response to movement of said reaction member in one direction for controlling said electrically operable means; and a second circuit controller operated in response to movement of said reaction member in the other direction for oppositely controlling said electrically operable means.

5. In a control system of the class wherein a load is operated by a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, the combination therewith of: a differential transmission having a planetary gear member, a sun gear member for rotating said planetary gear member, and 'a ring gear member capable of movement about the axis of said sun gear; resilient means secured to said ring gear for yieldingly restraining movement of said ring gear in either direction from one position; a pair of circuit controllers for controlling said electrically operable means; and an arm carried by said ring gear for alternately operating said circuit controllers upon alternate movement of said ring gear from said one position.

6. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft connected to said first rotary member; a second rotary member for moving the belt and spaced from said first rotary member; a variable ratio transmission mechanism foroperating said second rotary member, and having an input shaft operated by said driving shaft; means movable in accordance with the torque load on said input shaft; means resiliently restraining movement of said movable means under the influence of said torque load; and means operated upon sufiicient movement of the movable means to vary the ratio of transmission to correct the torque load on said input shaft.

7. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft connected to said first rotary member; a second rotary member for moving the belt and spaced from said first rotary member; a variable ratio transmission mechanism for operating said second rotary member, and having an input shaft operated by said driving shaft; means movable in accordance with the torque load on said input shaft; means resiliently restraining movement of said movable means under the influence of said torque load; a pair of means respectively engageable with the movable member upon predetermined opposite movement thereof from a pre-set position for oppositely adjusting the ratio of transmission to correct the torque load on said input shaft and so that said movable means returns toward said pre-set position.

8. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft connected to said first rotary member; a second rotary member for moving the belt and spaced from said first rotary member; a variable ratio transmission mechanism for operating said second rotary member, and having an input shaft operated by said driving shaft; means movable in accordance with the torque load on said input shaft; means resiliently restraining movement of said movable means under the influence of said torque load; a pair of means respectively engageable with the movable member upon predetermined opposite movement thereof from a pre-set position for oppositely adjusting the ratio of transmission to correct the torque load on said input shaft and so that said movable means returns toward said pre-set position; the spacing of said pair of means together with the characteristics of said resilient means determining the limits of torque load variation on said input shaft.

9. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft connected to said first rotary member; a second rotary member for moving the belt and spaced from said first ro-.

tary member; a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, said variable ratio transmission having an output shaft connected to said second rotary member and an input shaft; a differential transmission including a driving member driven by said driving shaft, a driven member connected to said input shaft, and a reaction member; means supporting the reaction member for limited angular movement; resilient means restraining movement of said reaction member; and a circuit controller operated upon movement of said reaction member for controlling said electrically operable means.

10. In combination: a continuous conveyor belt; a first rotary member for moving said belt; a driving shaft connected to said first rotary member; a second rotary member for moving the belt and spaced from said first rotary member; a variable ratio transmission mechanism having electrically operable means for adjusting the ratio of transmission, said variable ratio transmission having an output shaft connected to said second rotary member and an input shaft; a differential transmission including a driving member driven by said driving shaft, a driven member connected to said input shaft, and a reaction member; means resiliently restraining movement of said reaction member in either direction from one position; a first circuit controller operated in response to movement of said reaction member in onedirection for controlling said electrically operable means;

and a second circuit controller operated in response to movement of said reaction member in the other direction for oppositely controlling said electrically operable means.

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS Madle Apr. 12, 1938 Bishop Aug. 13, 1938 5 Webb Sept. 20, 1938 Madle May 9, 1939 Pechy Aug. 1, 1939 10 Perry Aug. 1, 1939 Regan Apr. 23, 1940 Arnold et a]. June 18, 1940 Mageoch Nov. 26, 1940 Rieci Mar. 17, 1942. Haynes Sept. 22, 1942 Morrill Nov. 13, 1945 Wolf Nov. 10, 1953 

